Amazon is upping its game in the competition between online video services. Today, it announced a deal with Viacom that will add all kinds of new TV programming to its library.

As NPR's Laura Sydell reports, Netflix still dominates the business, but its place at the top is a bit shakier today.

LAURA SYDELL, BYLINE: Viacom controls popular cable channels like MTV, Comedy Central, Nickelodeon and VH1. That means Amazon is about to get some popular shows.

(SOUNDBITE OF SHOW, "HOT IN CLEVELAND")

BETTY WHITE: "Hot in Cleveland" is recorded in front of a live studio audience.

(SOUNDBITE OF TELEVISION SHOWS)

SYDELL: The agreement with Viacom comes on the heels of other deals for content with Fox and CBS. Michael McGuire says Amazon is likely to pose a serious threat to Netflix, which is currently the most popular service for streaming movies and television over the Internet.

Netflix may have much of the same content that Amazon is getting, but Amazon has its own tablet computer, the Kindle Fire. Netflix? It's just online.

MICHAEL MCGUIRE: They don't have a device or something like that. Right? Like a Kindle Fire is a very powerful anchor for Amazon when it comes to that because it's a useful device in and of itself.

SYDELL: Amazon's growing prominence as a streaming service just adds to the competition for Netflix. This week, Verizon also announced a deal that it would launch a streaming service with Red Box.

Ultimately, says McGuire, we are likely to see a lot more deals like this and it's going to be good for consumers.

MCGUIRE: A lot of these devices and these new services give consumers a great deal of flexibility about when, where and how they consume content.

SYDELL: As McGuire points out, Apple is also interested in delivering TV and movies on its devices, the iPad and the iPhone, and those devices have a cache that Amazon's Kindle Fire doesn't have.